No-tillage planting is an increasingly utilized planting technique in agriculture in which a furrow opener is typically provided in the form of a rotatable disc opener that fractures the soil into a furrow of disturbed soil. A seed boot is typically located to one side of the disc for placing seed into the furrow before closing the furrow. In planting the seed it is further desirable to deposit fertilizer in proximity to the seed in which a seed row is positioned upwardly and to one side of a fertilizer row in a single pass. U.S. Pat. Nos. 7,004,090 and 7,152,539 both belonging to Swanson disclose examples of disc openers in which a wing is supported on the seed boot to support liquid fertilizer injection nozzles arranged to dispense liquid fertilizer in proximity to the seed row. The configuration of the injectors however causes the injectors to be readily subject to plugging which prevents effective fertilizer placement. Furthermore the location of the wing with the fertilizer nozzles thereon is supported on the seed boot so that the openers are unable to adequately place a seed row in a desired upward and laterally offset placement relative to a fertilizer row.
U.S. Pat. No. 6,032,593 belonging to Wendling et al. discloses a further example of a drill opener for positioning seed and fertilizer rows in a single pass, however in order to do so a complex mechanism involving two discs for forming separate furrows is taught to be required. The resulting configuration is accordingly costly to manufacture and requires more maintenance than a single disc opener.
Another example of a disc opener which attempts to place a seed row spaced from a fertilizer row in a single pass is available by Atom-Jet Industries of Brandon, Canada. A scraper is taught for attachment to a Case IH SDX disc opener in which a horizontal plate is supported integrally with the scraper to widen the furrow formed by the disc and form a shelf in the furrow while doing so. A deflector plate is provided in an upright orientation between a seed tube and a fertilizer tube between the scraper and the disc with the intention of depositing fertilizer at the bottom of the disc furrow while seed is intended to be deposited on the shelf formed by the horizontal plate. As the shelf is open to the deeper part of the furrow and the configuration of the seed boot is arranged to drop seed from above onto the seed shelf, it is possible that seed can readily bounce off of the seed shelf and into the deeper portion of the furrow adjacent the fertilizer where it is subject to damage from high concentrations of fertilizer.
Disc type furrow openers are known with gauge wheels adjacent to the disc to gauge the depth of penetration of the disc, and thus gauge the depth of the furrow made. Trailing arm furrow opener assemblies are known where a trailing arm is pivotally attached at a front end to a seeder implement frame, and a furrow opener is attached to the arm, and the rear end of the arm is supported by a packer wheel. The arm is biased downward to push the furrow opener into the ground, and the depth of penetration is gauged by the relative vertical positions of the furrow opener and packer wheel.
Since the gauge wheel is very close to the furrow opener the depth adjustment is more precise than with the packer wheel on the end of the trailing arm, however more packing force is available with the trailing arm system. Thus in dry conditions where maximum packing force is desired the trailing arm may be preferred, while in wetter conditions where packing is not as critical, the gauge wheel depth adjustment may be preferred.